3d system and method for guiding objects

ABSTRACT

An intraoral 3D scanner includes a probe light source configured to generate a probe light such that the probe light is transmitted towards the dental situation; a camera including an array of sensor elements, the camera being arranged such that the probe light from the dental situation is transmitted to the array of sensor elements, wherein the camera is configured to create images of the dental situation from which a point cloud is generated, and a guiding system configured to guide relative movement of the intraoral 3D scanner towards the dental situation, wherein the camera is part of the guiding system, the camera is configured to record images from which a relative position of the intraoral 3D scanner and the dental situation is determined, such that based on the relative position, the guiding system is configured to provide a positioning signal in the form of a positioning color code.

The present application is a continuation of U.S. application Ser. No.15/685,417, which was filed on Aug. 24, 2017, which is a continuation ofU.S. application Ser. No. 15/089,855, which was filed on Apr. 4, 2016and is now U.S. Pat. No. 9,763,746, which is a continuation ofapplication Ser. No. 14/110,184, which was filed in the US on Dec. 5,2013 and is now U.S. Pat. No. 9,320,572, and which is a national stageapplication of PCT/DK2012/050112, filed on Apr. 4, 2012, and whichclaims the priority of U.S. Provisional Application No. 61/472,858,filed on Apr. 7, 2011, and Danish patent application number PA 201100270, filed on Apr. 7, 2011. The contents of U.S. application Ser. No.15/685,417; U.S. application Ser. No. 15/089,855; U.S. application Ser.No. 14/110,184; PCT/DK2012/050112; U.S. Provisional Application No.61/472,858; and Danish patent application number PA 2011 00270 are allincorporated herein by reference.

The disclosure relates to a method and a 3D guiding system for providinga guided relative movement of a first and a second object. Moreparticularly, the disclosure relates to a method and a 3D guiding systemconfigured for calculating information for guiding the relative movementof the first and second objects towards a first preferred relativearrangement, which may be determined from a 3D model of the secondobject. The present relative position of the two objects is tracked by3D scanning of the second object.

Disclosed is a 3D guiding system for guiding a relative movement of afirst object and a second object, where the system is configured forbeing arranged in relation to said first object, and where said 3Dguiding system comprises:

-   -   a 3D scanner configured for performing a 3D scanning of the        second object;    -   a non-transitory computer-readable medium configured for at        least temporary storing:        -   a 3D model of the second object;        -   program code for determining a present relative arrangement            of the first and second objects from a result of a 3D            scanning of the second object; and        -   program code for calculating information for guiding the            relative movement of the first and second objects towards a            first preferred relative arrangement from said present            relative arrangement.

Disclosed is a method for providing a guided relative movement of afirst object and a second object, said method comprising:

-   -   obtaining the first object onto which a 3D guiding system is        attached, where said 3D guiding system comprises a 3D scanner;    -   obtaining the second object and a 3D model of the second object,        and deriving from said 3D model a first preferred relative        arrangement between the first and second objects;    -   performing a movement procedure comprising:        -   a) 3D scanning at least a region of said second object using            said 3D scanner and determining a present relative            arrangement of the first and second objects from a result of            the 3D scanning;        -   b) calculating information for guiding the relative movement            of the first and second objects towards said first preferred            relative arrangement from said present relative arrangement;            and        -   c) providing a relative movement of said first and second            objects towards the first preferred relative arrangement,            where the calculated information is used for guiding the            relative movement.

In some embodiments, the non-transitory computer-readable medium furtherstores program code for deriving from said 3D model a first preferredrelative arrangement between the first and second objects. Deriving thefirst preferred relative arrangement may involve resource demandingcalculations and in some embodiments, it may be preferred that firstpreferred relative arrangement is derived on a separate system fromwhich it then transferred to the 3D guiding system.

In some embodiments, the second object is part of the system. In someembodiments, the second object and the first object are autonomousparts.

In some embodiments, the system and/or the 3D guiding system comprises adevice configured to provide a relative movement of said first andsecond objects towards the first preferred relative arrangement, wherethe calculated information is used for guiding the relative movement.

In some embodiments, the 3D guiding system comprises a signal lightsource configured to provide said information by projecting a guidingsignal onto a target region of the second object.

In some embodiments, the system and/or the 3D guiding system comprises anon-transitory computer readable medium having one or more computerinstructions stored thereon, where said computer instructions comprisesinstructions for performing the method according to the disclosure.

An advantage of the present disclosure over the prior art is that thepresent relative arrangement of the first and second objects isdetermined without using an external localization device.

In some embodiments, determining the present relative arrangement of thefirst and second objects comprises pairing the obtained 3D model of thesecond object and the result of the 3D scanning, such that the result ofthe 3D scanning is compared to the obtained 3D model and from thecomparison the present relative arrangement of the first and secondobjects is determined.

The comparison may comprise a rotation and a translation of the obtained3D model and the result of the 3D scanning such that they are alignedcorrectly, e.g. with corresponding surfaces coinciding. Based on theextent of rotation and translation required to provide a correctalignment, the present relative arrangement can be determined withrespect to the first preferred relative arrangement.

The result of the 3D scanning may be used to generate a new 3D modelmapping the surface and/or the interior structure of the second objectin the scanned region. Pairing the new 3D model and the obtained 3Dmodel may then be used to determine the present relative orientation ofthe first and second objects with respect to the first preferredrelative arrangement.

In some embodiments, the obtained 3D model relates to a surface of thesecond object, such that the 3D model comprises data relating to asurface of a scanned region of said second object. This may for examplebe the case when the 3D scanner is an optical scanner and the scannedregion of the second object is such that light is reflected from itssurface. It may also be the case when the 3D scanner is based on focusscanning, such as in the 3Shape TRIOS intraoral scanner, and the surfaceof the second object is at least partly translucent, which e.g. can bethe case for teeth.

Further characteristics of the second object may be added to the 3Dmodel obtained by scanning the surface of the second object. Thesecharacteristics may comprise an interior structure in the second object.This may be the case when the second object is a dental situation or abody part of a patient where the further characteristics may be obtainede.g. by X-ray imaging of the second object. The further characteristicsmay be integrated in the 3D model of the second object.

In some embodiments obtaining said 3D model comprises a sub-surfacescanning of the scanned region and/or the target region of said secondobject, such as by Magnetic Resonance Imaging, by an X-ray scanning orby a CT scanning of the second object, such that the 3D model comprisesdata relating to an interior structure of said second object.

In some embodiments, the 3D scanner of the guiding system is configuredfor sub-surface scanning. The 3D scanner may e.g. be a CT scanner wherethe surface in the scanned region of the second object is at leastpartly transparent to the X-ray signals of the CT scanner. The movementprocedure can then be guided based on the knowledge of the interiorstructure and on the measurements provided by the CT scanner. Likewise,the first preferred relative arrangement and the information can then bederived from the interior structure, such that a guiding signaldisplayed e.g. on the surface of the second object is derived from theinterior structure.

In some embodiments, the obtained 3D model comprises both a surface andan interior structure of the second object.

In a dental application of the disclosure, the obtained 3D model maycomprise both the surface and interior structure of a set of teeth. If anew 3D model is generated from the result of the 3D scanning, the set ofteeth in the new 3D model may virtually be rotated and/or translated tocoincide with the set of teeth in the obtained model.

In a surgical application of the disclosure, the obtained 3D model maycomprise both the surface, such as the skin surface, and an interiorstructure of a body part, such as veins, arteries and bones.

In some embodiments, the shape of first object is taken into accountwhen deriving the first preferred relative arrangement between the firstand second objects.

This may be the case e.g. when a cross sectional shape of the firstobject at a point of contact with the second object has no rotationsymmetry or a finite rotational symmetry, such as a two-fold or athree-fold symmetry.

The reduced rotation symmetry may be around a longitudinal axis of thefirst object. When the first object comprises a surgical scalpel, theremay be no rotation symmetry since the surgical scalpel has a preferredorientation relative to the surface with the sharp edge facing thesurface which it is intended to cut into.

A dental drill also has a shape with a preferred relative arrangementrelative to a tooth from which toot material is to be removed by thedrill or relative to the mandibular/maxillary from which bone materialis to be removed in order to make space for an implant.

In some embodiments, the 3D guiding system comprises several parts.

In some embodiments, the 3D guiding system may be an integrated systemwith all parts integrated in one coherent system.

In some embodiments, the 3D guiding system comprises two or moreseparate parts that are distributed with a distance between at leastsome of said parts. For a 3D guiding system comprising separate parts,all of these separate parts may be attached to the first object. Theattachment may be direct or indirect, such as an attachment via anotherof the separate parts.

In some embodiments, the distance between the first and second objectsis determined from the result of the 3D scanning. The scanning may e.g.comprise a time of flight based measurement of the distance and/or ascaled version of the 3D model is fitted to the result of the 3Dscanning. A scaling factor showing the size of the scaled version of the3D model at different distances can be used to determine the distance.

In some embodiments, the first preferred relative arrangement is suchthat the first object is adjacent to the second object with a preferredorientation relative to the second object. This may be the case for anumber of applications of the disclosure, such as in dental treatments,in surgical operations, in the gluing together two objects, in parking acar relative to another car or an obstacle, or in docking one object inrelation to another. In the context of the present disclosure, thephrase “adjacent” may refer to an arrangement where one object is nextto but not necessarily connected with a another object. The object canalso be in contact, such as in contact with no penetration of one objectinto the other.

In some embodiments, the first preferred relative arrangement is suchthat there is a well-defined and/or predetermined distance between thefirst object and the second object with a preferred relative orientationof the two objects. This may e.g. be the case when the disclosure isapplied in relation to a welding procedure or a parking of a vehicle.

In the context of the present disclosure the phrase “X determined fromY” may refer to the case wherein determining X takes into account Y.Other parameters may still influence the value of X. X may for instancebe the present relative arrangement while Y may be a result of the 3Dscanning.

In the context of the present disclosure the phrase “towards the firstpreferred relative arrangement” may refer to a relative movement whichbrings the first and second object closer to the first preferredrelative arrangement, such as a relative movement which brings the firstand second object to the first preferred relative arrangement.

During the relative motion of the first and second objects, the secondobject may be stationary relative to a reference frame, while the firstobject is moved towards the second object. The method may then be forproviding a guided movement of the first object.

This may be the case when the disclosure is used in relation to a dentalor a surgical procedure on a patient. In relation to dental treatmentsthe disclosure may be used to guide e.g. a dental drilling tool used todrill into a tooth or the mandibular or maxillary bone of the patient.In relation to surgical treatments the disclosure may be used to guidee.g. a surgical scalpel used to provide a cut in the patient.

During the relative movement of the first and second objects, the firstobject may be stationary relative to a reference frame, while the secondobject is moved towards the first object. The method may then be forproviding a guided movement of the second object.

Such a configuration may e.g. be used when the first object is theheavier of the first and second objects.

The relative movement of the first and second objects may comprise amovement of both the first object and the second object relative to areference frame. This may e.g. be the case when both the first objectand the second object can be moved in a controlled manner.

The movement procedure may involve one or more steps that are performedin real-time. One or more of a), b) and c) may be performed inreal-time.

The 3D scanning of the scanned region of the second object may beperformed in real-time. The calculation of the information may beperformed in real-time.

In some embodiments, the 3D guiding system is configured for 3D scanningof the scanned region of the second object and/or for calculation of theinformation and/or for displaying said information in real-time.

The information may be displayed in real—both when a human operator anda robotic device or another machine provides the relative motion of thefirst and second objects.

In some embodiments, the 3D guiding system is configured for executingthe program code for determining the present relative arrangement and/orfor executing the program code for calculating information in real-time.

In the context of the present disclosure, the phrase “real-time” refersto the situation where the function that is performed in real-time issufficiently rapid such that e.g. a guiding signal is providedsufficiently rapid such that an operator can adjust the relativemovement of the first and second objects in due time.

For dental and/or surgical applications of the disclosure, the phrase“real-time” may be used for situations where the function occurs withina time frame of seconds, such that the information can be calculated andprovided to the dentist or doctor in a manner such that the informationis provided with a rate that is faster than the movement of the dentaldrilling tool or the scalpel.

Real-time may mean in that the function occurs within a time interval,where said time interval is less than about 60 seconds, such as lessthan about 30 seconds, such as less than about 15 seconds, such as lessthan about 10 seconds, such as less than about 5 seconds, such as lessthan about 2 seconds, such as less than about 1 second, such as lessthan about 0.5 seconds, such as less than about 0.2 seconds, such asless than about 0.1 seconds, such as less than about 0.05 seconds, suchas less than about 0.02 seconds, such as less than about 0.01 seconds,such as less than about 0.005 seconds, such as less than about 0.002seconds, such as less than about 0.001 seconds.

In some embodiments, the relative movement is controlled by a humanoperator. The first object and/or the second object may be a handhelddevice which the operator can move relative to the other object. Theoperator may also control the relative movement via a mechanical deviceconfigured for translating, moving, tilting or rotating an object, sucha mechanical arm, an engine, or a stage.

In some embodiments, the relative movement is computer controlled. Thismay e.g. be the case for a robotic device according to the presentdisclosure, where the 3D guiding system and/or method assist the roboticdevice in the relative motion of the first and second objects.

In some embodiments, the movement procedure comprises repeating one ormore of a), b) and c) a number of times, such that the first and secondobjects may gradually approach the first preferred relative arrangement.

The repetition of a), b) and c) may be such that both a) and b) areperformed for each repetition of c). The present relative arrangement ofthe first and second objects is then determined and the information forguiding the relative motion is then calculated for each relativemovement of the objects.

The repetition of a), b) and c) may be such that either a) or b) isperformed for one repetition of c). This may be the case when thepresent relative arrangement of the first and second objects isdetermined for each relative movement of the objects, while thecalculation of the information for guiding the relative motion only iscalculated when a significant change of the relative arrangement hasoccurred.

In some embodiments, the relative movement of the first and secondobjects is substantially continuous and a) and/or b) are performedduring the relative movement. For several applications of thedisclosure, the relative motion of the first and second objects issubstantially continuous such as when a human operator or a roboticdevice moves one object towards another in a smooth movement while usingthe calculated information for guiding the motion.

The determining of the present relative arrangement and the calculationof the information may be performed on the fly. Both a) and b) shouldthen preferably be sufficiently fast compared with the speed of themovement, such that the information is provided in due time forappropriate changes in e.g. the direction of the relative movement to bemade. In some embodiments, b) is only performed if a) indicates that asignificant change in the relative arrangement has occurred since theprevious calculation of the information.

In some embodiments, the 3D guiding system is configured forcontinuously executing the program code for determining the presentrelative arrangement and/or for continuously executing the program codefor calculating information and/or for executing the program code forderiving further preferred relative arrangements, such that theseprogram codes can be executed continuously during a relative movement ofthe first and second objects.

In some embodiments, the method comprises arranging said first andsecond objects in an initial relative arrangement and where saidinformation is used for guiding the first and second objects from theinitial relative arrangement to the first preferred relativearrangement.

In some embodiments, the calculation of the information also provides oris based on a calculated planned movement, such as a planned movementbased on a previous relative arrangement and the first preferredrelative arrangement of the first and second objects. The previousrelative arrangement may be the initial relative arrangement or arelative arrangement occurring between the initial and the currentrelative arrangement.

Not all steps needs to be performed in real-time. For instance thecalculation of information may occur with a lower repetition rate thane.g. the 3D scanning. When the 3D scanning shows that the relativemovement of the first and second objects occurs as planned, there is noneed for providing information to the operator after the acquiring ofeach 3D scan.

In some embodiments, the 3D guiding system comprises a motion sensoradapted to perform a motion measurement of the movement of the firstobject

When the 3D guiding system comprises a motion sensor the presentrelative arrangement of the first and second objects can determined fromsaid motion measurement. The present relative arrangement can bedetermined from the motion measurement alone or in combination withinformation derived from a 3D scanning of the second object and the 3Dmodel.

In some embodiments, the program code for determining said presentrelative arrangement takes into account a result of the motionmeasurement, such that the present relative arrangement of the first andsecond objects can be determined from said motion measurement.

In some embodiments, the 3D guiding system comprises an orientationsensor adapted to perform an orientation measurement of the firstobject.

When the 3D guiding system comprises an orientation sensor the presentrelative arrangement of the first and second objects is determined fromsaid orientation measurement. The present relative arrangement can bedetermined from the orientation measurement alone or in combination withinformation derived from a 3D scanning of the second object and the 3Dmodel.

In some embodiments, the program code for determining the presentrelative arrangement takes into account a result of the orientationmeasurement, such that the present relative arrangement of the first andsecond objects can be determined from said orientation measurement.

The present relative arrangement can be determined from the orientationmeasurement and the motion measurement in combination.

From a well-defined initial relative arrangement the motion sensorand/or the orientation sensors may be used to determine the presentrelative arrangement at various positions on the way to the firstpreferred relative arrangement.

In some embodiments, the 3D scanning is performed using said 3D scanner.

In some embodiments, the first object contacts said second object in atarget region of the second object when the first and second objects arearranged in said first preferred relative arrangement. The target regionmay comprise the point of contact between the first and second objectsand optionally the immediately surrounding surface of the second object.

In some embodiments, the first object comprises a distal end which isconfigured to contact the target region of the second object. The distalend may comprise an entry part configured to enter the target region ofsaid second object. The shape of the entry part of said first object maybe taken into account when the first preferred relative arrangement isderived.

In some embodiments, the first object comprises a proximal end which isconfigured for being held by an operator or by a mechanical device suchas a robot.

In some embodiments, the information is displayed using an informationdisplaying device of said 3D guiding system, where the informationdisplaying device is configured for displaying the information to anoperator.

The information displaying device may be an integral part of the 3Dguiding system which is arranged at the first object. In the case wherethe first object is a “handheld” device, the information displayingdevice can be part of what is handheld.

The information displaying device can in principle also be arranged atsome distance from the first object, such as e.g. when the informationdisplaying device is a device connected to the handheld first object viaa wired or a wireless connection.

In some embodiments, the 3D guiding system is attached to the firstobject. Instead of being attached to the first objects, the guidingsystem may be an integral part of it.

When the relative arrangement of the first and second objects isinfluenced by other movements than the relative movement provided bye.g. a human operator, such a displaying of the information may beessential for obtaining the first preferred relative arrangement betweenthe first and second objects. In the case of a dental or surgicaltreatment on a patient, the patient may move and this patient movementmay be accounted for by real-time determining the relative positionand/or real-time calculation of the information.

In some embodiments, the second object comprises a one or more unitsthat are to be welded or glued together.

In some embodiments, the method comprises estimating a surfacedeformation of the second object when the second object e.g. is bend. Inone case, a 3D model of a patient is obtained while the patent issitting in one posture while during the movement of a scalpel towards anentry point on the patient's body, the patient is sitting in a differentposture. This change of posture may cause problems. When the methodcomprises an estimation of the change of the patient's body during thechange of posture, such problems may be avoided.

In some embodiments, the calculation of the information for guiding thefirst and second objects towards said first preferred relativearrangement takes into account the shape of the entry part of said firstobject.

In some embodiments, the first object comprises a drilling tool. Thedrilling tool may comprise a surgical or dental drilling tool configuredfor drilling into a body part, a tooth or the mandibular or maxillarybone of the patient.

In some embodiments, the first object comprises a dental drilling toolconfigured for drilling into a tooth or the mandibular or maxillary-boneof the patient.

In some embodiments, the method comprises deriving further preferredrelative arrangements between the first and the second objects. Thefurther preferred relative arrangements may comprise one or moreadditional preferred relative arrangements. The first preferred relativearrangement and the further additional preferred relative arrangementsmay together form a preferred path of the relative movement of the firstand second objects. The method may comprise guiding said relativemovement according to said preferred path. The 3D guiding system may beconfigured for guiding said relative movement according to saidpreferred path.

In some embodiments, the 3D guiding system comprises program code forderiving further preferred relative arrangements between the first andthe second objects.

At least part of the further preferred relative arrangements may be suchthat they define intermediate relative arrangements of a path defined bythe initial and the first preferred relative arrangement.

At least part of the further preferred relative arrangements may be suchthat they define an extension of a path defined by the initial and thefirst preferred relative arrangement, i.e. at least part of the furtherpreferred relative arrangements represents a continuation of a relativemovement of the first and second object in respect to the relativemovement from the initial to the first preferred relative arrangement.

In some embodiments, one or more of said further preferred relativearrangements corresponds to an arrangement where at least a portion ofthe distal end of the first object is located below the surface of thesecond object.

In the context of the present disclosure, the phrase “below the surface”may refer to a region located opposite to the first object relative tothe surface of the second object when the objects are arranged in theinitial relative arrangement.

In some embodiments, obtaining a 3D model of the second object comprisesscanning at least a portion of the second object and/or scanning atleast a portion of an impression of the second object, such that the 3Dmodel comprises data relating to the surface of said second object. Thescanned portion of the second object or of the impression of the secondobject may correspond to the region of the second object scanned usingthe 3D scanner during the movement procedure.

In some embodiments, the 3D model of the second object comprises datarelating to the second object and data relating to a plannedmodification of the second object

In some embodiments, the second object relates to the mandibular and/ormaxillary of a patient and said planned modification corresponds to adental implant or a hole which is planned to be defined in themandibular or maxillary for accepting said dental implant. In someembodiments, the modification is planned based on information relatingto the internal structure and/or the surface of the second object.

In some embodiments, the planned modification is taken into account whenderiving the first preferred relative arrangement from said 3D model.

In some embodiments, the planned modification is taken into account bythe program code for deriving the first preferred relative arrangementfrom said 3D model.

In some embodiments, the 3D model of the second object is obtained priorto the movement procedure.

In some embodiments, the second object comprises a part a patient body,such as a region of the patient body in which a surgical procedure is tobe performed, such as a region comprising skin, muscular tissue, bonestructure, and/or blood vessels.

In some embodiments, obtaining said 3D model comprises data from ascanning of the surface of the scanned region of said second object.

In some embodiments, scanning the surface of the scanned region of saidsecond object provides a virtual 3D representation of the second objectfrom which the 3D model may be obtained. The virtual 3D representationcan e.g. be a point cloud from which the 3D model is generated bytriangulation.

In some embodiments, a sub-surface scanning of the interior structure ofthe scanned region of said second object provides a virtual 3Drepresentation of the interior structure of the second object from whichthe 3D model may be obtained. In some embodiments, the virtual 3Drepresentation is at least in part obtained by a sub-surface scanning ofthe scanned region and/or target region of said second object, such asby Magnetic Resonance Imaging, by an X-ray scanning or by a CT scanningof the second object.

In some embodiments, the interior structure of the second objectcomprises nerves, root parts of teeth, or the mandibular and/ormaxillary bone structure.

In some embodiments, the interior structure of the second objectcomprises nerves, bone structure, arteries, and veins of a patient'sbody.

In some embodiments, the 3D model of the second object is obtained bycombining data obtained by scanning its surface and data obtained byscanning its interior structure, such that the 3D model comprises datarelating to the surface and data relating to the interior structure ofthe second object.

In some embodiments, the 3D model of the second object comprises a 2DX-ray scan of the second object arranged relative to a 3D scanning ofthe surface of the second object, i.e. the 2D X-ray scan of the secondobject is arranged relative to a surface of the second object in the 3Dmodel.

The target region may be part of the scanned region, such that thetarget region is scanned during the 3D scanning. The target region maybe at least partly displaced from the scanned region, such that the 3Dscanning provides a scan comprising one or more regions of the secondobject located outside the target region. The 3D scanning may comprise ascanning of off-target regions of the second object, where theseoff-target regions are linked to the target regions, such thatdetermining the location of the off-target regions is used to determinethe relative arrangement of the first and second object. This may be thecase in applications where the form of the second object is well-definedand determined prior to applying the disclosure or where alignment marksare provided on a part of the second object which is displaced from thetarget region. The displaced scanned region is then scanned while theentry portion of the first object is arranged relative to the targetregion of the second object according to the first preferred relativearrangement.

In some embodiments, the 3D model is provided using a non-contactimaging method, such as a method based on electromagnetic or acousticwaves.

In some embodiments, the 3D guiding system is configured to provide a 3Dscanning of the at least the scanned region of the second object.

In some embodiments, 3D scanning a region of the second object providesa mapping of the surface of the second object in the scanned region.

In some embodiments, 3D scanning a region of the second object providesa mapping of an interior part of the second object in the scannedregion.

In some embodiments, each image or sub-scan is obtained in one shot,i.e. each sub-scan is acquired instantaneously without the use of e.g. aline-scanning technique. In a line-scanning technique a line of light isscanned across the scanning area and e.g. reflected light is collectedover time as the line scans across the scanning area.

In some embodiments, the information is displayed by projecting aguiding signal onto the region of the second object.

In some embodiments, the information displaying device of the 3D guidingsystem comprises a projecting device configured for projecting a guidingsignal onto a region of the second object, where the guiding signal isbased on the information.

The guiding signal may be projected onto a point of contact, wherecontact is established between the first and second objects whenarranged according to the first preferred relative arrangement.

The guiding signal may be guided towards a point of entry, where anentry part of said first object is to enter the target region of thesecond object.

The region of the second object onto which the guiding signal isprojected may comprise the target region or at least part of said targetregion.

In some embodiments, the information displaying device of the 3D guidingsystem comprises a display and said information is displayed on saiddisplay as a guiding signal.

In some embodiments, the guiding signal comprises a positioning signal.The positioning signal may show the position of the target region onsaid second object i.e. the positioning signal may show where the distalend of the first object is to contact the second object.

The positioning signal may provide information relating to the relativeposition of the first object and the second object, such as to theposition of the first object relative to a preferred path.

In some embodiments, the guiding signal comprises an orientation signal.The orientation signal may provide information relating to the relativeorientation of the first object and the second object, such as to therelative orientation of the first and second objects compared to therelative orientation of a preferred path. The orientation signal mayprovide information relating to a difference in the orientation of thepresent relative arrangement compared to the orientation of the firstpreferred relative arrangement.

In some embodiments, the positioning signal comprises a relativelybrighter spot and said orientation signal comprises a relatively lessbright spot or vice versa.

In some embodiments, the positioning signal comprises a relativelysmaller area spot and said orientation signal comprises a relativelylarger area spot or vice versa.

In some embodiments, the positioning signal comprises a positioningcolor code, preferably configured such that the color of the positionindicator changes when the first and second objects are approaching eachother towards the first preferred relative arrangement.

In some embodiments, the orientation signal comprises an orientationcolor code, preferably configured such that the color of the orientationindicator changes when the first and second objects are approaching eachother towards the first preferred relative arrangement.

In some embodiments, a cross sectional geometry of said positioningsignal and/or of said orientation signal is selected from the group of across, a dot, a circle, or a polygon, such as a triangle, a square,rectangle, or a pentagon.

In some embodiments, the guiding signal comprises an indicator signaland the orientation signal coincides with said indicator signal when thefirst and second objects are arranged according to the orientation ofthe first preferred relative arrangement.

In some embodiments, the guiding signal comprises a distance indicatorproviding information relating to the distance between the first andsecond objects.

The orientation of the first object relative to a position in the targetregion of the second object may be expressed using a sphericalcoordinate system, where the spherical coordinate system is arrangedsuch that its origin coincides with said position in the target regionand the zenith direction coincides with the surface normal of the secondobject at said position. The position in the target region may be apoint of entry wherein the entry part of the first object is to enterthe second object. The preferred arrangement of the first objectrelative to the second object may then be expressed as a preferredazimuthal angle and a preferred inclination. The distance between thefirst and second objects may then be measured as the radial distance ofthe entry part from the position.

In some embodiments, the positioning signal and said orientation signalare arranged concentrically at least for some arrangements of the firstand second objects. The orientation signal may be configured to surroundthe position signal at least when the present relative arrangement isclose to the first preferred relative arrangement or to a furtherpreferred relative arrangement.

In some embodiments, the 3D guiding system comprises means forcontrolling the position of the guiding signal based on the 3D scanningand the relative arrangement of the first and second objects.

In some embodiments, the position of the guiding signal is determinedvia the direction in which the guiding signal is emitted from a lightsource of the 3D guiding system. The means for controlling the positionof the guiding signal may then comprise beam controlling optics and/oractuators for controlling the arrangement of the guiding signal lightsource relative to the other parts of the 3D guiding system.

In some embodiments, the 3D guiding system is configured for obtaining apre-process plan describing a preferred path for the relativearrangement of the first and second objects during their relativemovement towards the first preferred relative arrangement. In someembodiments, a pre-process plan is provided, said pre-process plandescribing a preferred path for the relative arrangement of the firstand second objects during their relative movement. The relative motionmay be towards the first preferred relative arrangement. The relativemotion may extend further than the first preferred relative arrangementalong further preferred relative arrangements.

The preferred path may substantially be followed as the first and secondobjects approach the first preferred relative arrangement. Deviationsform said preferred path may be corrected in real-time by eitherbringing the relative movement back to the planned preferred path or byreal-time adapting the path.

The 3D scanning of the second object may provide a scanning of thesurface of the second object in its scanning part. Techniques know forthe skilled person may be used for this part of the procedure.

The concept of the disclosure is generic and may be applied in numerousapplications such as for dental treatments, surgical treatments,drilling in structures such as walls wherein e.g. electrical wiring orwater/gas pipes are present, or for welding or gluing differentstructures together.

The disclosure may also be applied for the alignment of largerstructures such as for parking cars or for docking one structure inrelation to another. The concept of the disclosure provides nolimitations to the size of the object and the first object may e.g. be ashop docking a harbor or a space shuttle docking to a space station.

The disclosure may be applied in medical treatments such as for placinga stent in a blood vessel when e.g. performing a balloon angioplasty ofthe coronary artery or for intragastric balloon surgery.

In some embodiments, the 3D scanning provides a reading of the presentrelative arrangement of the objects. This may comprise the relativeposition and orientation of the first and second objects. The distancebetween the first and second objects may be determined from theirrelative position and/or by direct measurement.

Such a reading may be provided by comparing the result of the 3Dscanning and the 3D model of the second object. In the case of a dentalprocedure, the 3D model may be of a set of teeth showing the surfaceand/or interior structure of the set of teeth. The 3D scanning mayprovide a virtual 3D representation of the surface of the set of teethas seen from e.g. a drilling tool. By comparing the 3D model and theresult of the 3D scanning, the present relative arrangement may beidentified. Information for guiding the drill towards its firstpreferred relative arrangement may then be calculated and theinformation may be displayed to the dentist who then may provide arelative movement wherein the drill is moved towards the target regionof the set of teeth. This movement procedure continues until the drillhas reached the position and orientation according to the firstpreferred relative arrangement.

The disclosure may be applied in relation to a dental treatment forguiding a dentist when performing an operation on the dental situationof a patient. It may of significant importance that contact between thedrill and the nerves in the teeth is avoided since a damaging of thesenerves may have severe effects for the patient.

The first object may then be a dental tool, such as a dental drillingtool, onto which the 3D guiding system is attached. The second objectmay comprise part of the dental situation of the patient, such as a partof the teeth and/or of the mandibular or maxillary bone of the patient.The 3D model of the second object may be obtained from a virtual 3Drepresentation of the dental situation by scanning the dental situation,such as by scanning the dental situation by means of an intraoralscanner and/or by scanning an impression of the dental situation.

The first preferred relative arrangement may then refer to anarrangement of the dental tool in relation to e.g. a tooth or themandibular or maxillary bone of the patient.

A 3D model of the dental situation of the patient may be provided from ascanning of the teeth and/or the mandibular or maxillary bone. Thesurface of the teeth may be scanned by means of an optical basedintraoral scanner or by scanning an impression of the dental situation.A CT-scan may provide knowledge of the location of the nerves in thedental situation and together with the scan of the surface of the set ofteeth form the 3D model used for calculating the first preferredrelative arrangement of the drill and the set of teeth. In fact the CTscanning may also provide information relating to the surface of thesecond object. The first preferred relative arrangement may be such thatthe drill contacts the surface of a tooth which is to be exposed to aprocedure. The preferred orientation may be such that the drill can movealong its longitudinal direction at least over some length withouthitting a nerve. When the dentist moves the dental drilling tool withthe attached 3D guiding system towards the dental situation, the 3Dguiding systems displays the relative position of the drill and thedental situation. The displaying may comprise projecting a positioningsignal onto the tooth in the target region where the drill touches thetooth, while the orientation signal may comprise a ring with a dotindicating the deviation of the azimuthal and inclination of the presentorientation from the azimuthal and inclination of the orientation of thefirst preferred relative arrangement. When the dentist changes theorientation of the drilling tool, the ring and dot changes such that thedentist is guided towards the preferred arrangement of the drillrelative to the dental situation of the patient.

When the disclosure is applied in relation to a dental implant treatmentthe first preferred relative arrangement of a dental drilling tool ande.g. the mandibular or maxillary bone of the patient such that thedental drilling tool is aligned to drill into the mandibular ormaxillary bone. Prior to the commencement of the implant procedure, thevital structures such as the inferior alveolar nerve or the sinus arepreferably identified. The shape and dimensions of the mandibular ormaxillary bone may also be mapped such that the implant may be arrangedin the most advantageous place and orientation. The 3D model of thedental situation of the set of teeth may be obtained from e.g. 2Dradiographs, such as orthopantomographs or periapicals, or from a CTscan. The planning may involve the use of 3D CAD/CAM software

In one work-flow for determining a first preferred relative arrangement,a CT scan of a patient's dental situation is obtained initially. From a3D model of the dental situation formed from the CT scan, the positionand orientation of an implant is planned. The position and orientationof the hole in the mandibular or maxillary which is to accept the dentalimplant is then planned from the planned implant position andorientation. From the planned hole/implant position and orientation, amodified 3D model of the second object is generated where the plannedimplant/implant hole is indicated. From the modified 3D model, the firstpreferred relative arrangement can be determined

The disclosure may also be applied in relation the surgical procedures.In this case the first object may comprise a scalpel tool adapted to cutopen the patient, where the 3D guiding system is attached to the scalpeltool. The second object may be the patient such that the 3D modelcomprises a model of the skin and preferably the parts of the bodyarranged below the skin of the patient. This may be blood vessels orbone structure. The first preferred relative arrangement may be suchthat a surgeon can cut open the patient in the target region withoutinflicting unnecessary damage to the patient once the guiding isfollowed by the surgeon. The position of the target region may beindicated with the position signal, which may comprise a cross or a dot.The orientation signal may be a larger ring surrounding the positionsignal. When cutting into the patient, i.e. bringing the scalpel furtherinto the patient's body, the preferred orientation may change andfurther preferred arrangements may be calculated based on the 3D model.The orientation signal may change accordingly as the scalpel progressesguiding the surgeon to perform the preferred cut such that the extent ofdamage is mitigated.

Access to the part of the body may have been provided prior to theprocess, such as prior to the part of the method involving obtaining a3D model of the second object. The 3D model may also be obtainedinitially and then a first procedure is performed to e.g. open the chestof the patient before the method according to the present disclosure isapplied.

The requirement to the precision in the relative arrangement of thefirst and second objects may be very strict, such that the firstpreferred relative arrangement is unique. The precision requirement maybe less strict, such that the first preferred relative arrangement maycomprise an interval of relative arrangements. For example a gluing toolmay have different azimuthal angles relative to an object onto which itis about to apply glue. When using a guiding signal comprising apositioning signal and/or an orientation signal the change of thesignals which indicate that the first preferred relative arrangement hasbeen reached may occur when the relative arrangement of the first andsecond objects is sufficiently close to the optimal relative arrangementsuch that it is within the required precision.

The 3D scanner of the 3D guiding system may comprise a number of parts,such as one or more probe light sources and one or more camerasconfigured to obtain a virtual 3D representation of said second object.

The 3D scanner may be constructed in various ways known to the skilledperson.

One realization of a 3D scanner comprises a camera comprising an arrayof sensor elements and a probe light source configured for generating aprobe light. The probe light may be transmitted towards the secondobject thereby illuminating at least the scanned region of the secondobject, and light returned from the second object may be transmitted tothe array of sensor elements. The 3D scanner may further comprise afirst optical system for imaging with a first depth of field on thecamera at least part of the transmitted light returned from the secondobject to the array of sensor elements and a focus plane shifting deviceconfigured for varying the position of the focus plane on the secondobject. Further, the 3D scanner may be configures to obtain at least oneimage from said array of sensor elements and to determining the in-focusposition(s) of each of a plurality of the sensor elements for a range offocus plane positions, or each of a plurality of groups of the sensorelements for a range of focus plane positions. The scanner may furtherbe configured for transforming the in-focus data into 3D coordinates.

The camera may comprise a lens and a sensor array such as a CCD or CMOSchip. In some embodiments, a filter placed in front of the sensor array.The effect of the filter may be that only light with approximately thedesired wavelength passes the filter. This makes it feasible to separatedifferent light sources in the 3D scanner and remove most of thebackground light. Alternatively, the camera may be color sensitive.

The camera may be arranged such that it is configured to record images,from where the relative position and orientation of the first and secondobjects may be determined.

The 3D guiding system may comprise one or more light sources such as aprobe light source for the 3D scanner and a signal light source forproviding a guiding signal. The light sources may be lasers, variableoutput-powered laser, light emitting diodes (LED), halogen spots orother spotlights. The generated light may be supplied directly from alight source arranged e.g. near a distal end of the first object, or itmay be supplied with optical waveguides, such as optical fibers. In someapplications it might be relevant to use monochromatic, coherent orpolarized light. Note that the light may be projected onto the surfaceof the second object without damaging the surface even when lasersprovide the light. The probe light source and/or the signal light sourcemay emit light in the ultraviolet range, in the visible range and/or inthe infrared range. The probe light source and/or the signal lightsource may be adapted to emit coherent light, polarized light,monochromatic light, or light at different frequencies, such as light intwo or more frequency ranges. Various filters may be applied to theprobe light source and/or to the signal light source.

The 3D guiding system may work with only one light source, but for manypurposes it is advantageous to have several such as at least two lightsources. One or more probe light sources may be used in the 3D scannerwhile one or more signal light sources may be configured to provide theguiding signal projected onto the second object.

For some applications, the light sources are preferably as small aspossible to minimize the dimensions of the 3D guiding system. It iscontemplated that the light source may have a cross sectionperpendicular to the direction of emitted light of less than 5 mm²,preferably less than 4 mm², for example less than 3 mm², such as lessthan 2 mm², for example less than 1 mm², such as less than 0.5 mm², forexample less than 0.25 mm².

Handheld embodiments of the invention may comprise motion sensors suchas accelerometers and/or gyros. These micro electro mechanical systems(MEMS) may measure all motion in 3D, i.e., both translations androtations for the three principal coordinate axes.

Disclosed is also a computer program product comprising program codemeans for causing a data processing system to perform the methodaccording to the present disclosure when said program code means areexecuted on the data processing system, and a computer program productcomprising a computer-readable medium having stored there on the programcode means.

In some embodiments, a touch sensor is arranged in connection with thedistal end of the first object, such that the touch sensor is adapted toregister contact with the second object. The touch sensor may comprise atactile component at the distal end. The touch sensor may be acapacitive sensor.

Disclosed is also a nontransitory computer readable medium storingthereon a computer program, where said computer program is configuredfor causing computer-assisted implementation of one or more parts of themethod according to the present disclosure.

Disclosed is a system for guiding a relative movement of a first objectand a second object, said system comprising:

-   -   a 3D guiding system configured for being attached onto the first        object, where said 3D guiding system comprises a 3D scanner;    -   a non-transitory computer-readable medium configured for at        least temporary storing        -   i. a 3D model of the second object;        -   ii. program code for deriving from said 3D model a first            preferred relative arrangement between the first and second            objects;        -   iii. program code for determining a present relative            arrangement of the first and second objects from a result of            a 3D scanning of the second object; and        -   iv. program code for calculating information for guiding the            relative movement of the first and second objects towards            said first preferred relative arrangement from said present            relative arrangement.

Embodiments

1. A method for providing a guided relative movement of a first objectand a second object, said method comprising:

-   -   obtaining the first object onto which a 3D guiding system is        attached, where said 3D guiding system comprises a 3D scanner;    -   obtaining the second object and a 3D model of the second object,        and deriving from said 3D model a first preferred relative        arrangement between the first and second objects;    -   performing a movement procedure comprising:        -   a) 3D scanning at least a region of said second object using            said 3D scanner and determining a present relative            arrangement of the first and second objects from a result of            the 3D scanning;        -   b) calculating information for guiding the relative movement            of the first and second objects towards said first preferred            relative arrangement from said present relative arrangement;            and        -   c) providing a relative movement of said first and second            objects towards the first preferred relative arrangement,            where the calculated information is used for guiding the            relative movement.

2. The method according to embodiment 1, wherein one or more of a), b)and c) are performed in real-time.

3. The method according to any of the previous embodiments, wherein themovement procedure comprises repeating one or more of a), b) and c) anumber of times.

4. The method according to any of the previous embodiments, wherein therelative movement of the first and second objects is substantiallycontinuous and a) and/or b) are performed during the relative movement.

5. The method according to any of the previous embodiments, wherein theinformation is displayed using an information displaying device of said3D guiding system.

6. The method according to any of the previous embodiments, wherein themethod comprises arranging said first and second objects in an initialrelative arrangement and where said information is used for guiding thefirst and second objects from the initial relative arrangement to thefirst preferred relative arrangement.

7. The method according to any of the previous embodiments, wherein the3D guiding system comprises a motion sensor adapted to perform a motionmeasurement of the movement of the first object, and where the presentrelative arrangement of the first and second objects is determined fromsaid motion measurement.

8. The method according to any of the previous embodiments, wherein the3D guiding system comprises an orientation sensor adapted to perform anorientation measurement of the first object, and where the presentrelative arrangement of the first and second objects is determined fromsaid orientation measurement.

9. The method according to any of the previous embodiments, wherein said3D scanning is performed in real-time.

10. The method according to any of the previous embodiments, whereinsaid information is calculated in real-time.

11. The method according to any of the previous embodiments, whereinsaid information is displayed in real-time.

12. The method according to any of the previous embodiments, whereinsaid first object contacts said second object in a target region of thesecond object when the first and second objects are arranged in saidfirst preferred relative arrangement.

13. The method according to any of the previous embodiments, whereinsaid first object comprises a distal end which is configured to contactthe target region of the second object.

14. The method according to any of the previous embodiments, whereinsaid distal end comprises an entry part configured to enter the targetregion of said second object.

15. The method according to any of the previous embodiments, whereinderiving the first preferred relative arrangement takes into account theshape of the entry part of said first object.

16. The method according to any of the previous embodiments, wherein thecalculation of the information for guiding the first and second objectstowards said first preferred relative arrangement takes into account theshape of the first object.

17. The method according to any of the previous embodiments, wherein thefirst object comprises a dental drilling tool configured for drillinginto a tooth or the mandibular or maxillary-bone of the patient.

18. The method according to any of the previous embodiments, wherein thefirst object comprises a scalpel.

19. The method according to any of the previous embodiments, wherein themethod comprises deriving further preferred relative arrangementsbetween the first and the second objects.

20. The method according to embodiment 19, wherein the first preferredrelative arrangement and the further additional preferred relativearrangements together forms a preferred path of the relative movement ofthe first and second objects, and said method comprises guiding saidrelative movement according to said preferred path.

21. The method according to any of the previous embodiments, wherein oneor more of said further preferred relative arrangements corresponds toan arrangement where at least a portion of the distal end of the firstobject is located below the surface of the second object.

22. The method according to any of the previous embodiments, whereinobtaining a 3D model of the second object comprises scanning at least aportion of the second object and/or scanning at least a portion of animpression of the second object.

23. The method according to any of the preceding embodiments wherein the3D model of the second object comprises data relating to the secondobject and data relating to a planned modification of the second object

24. The method according to any of the preceding embodiments wherein thesecond object relates to the mandibular and/or maxillary of a patientand said planned modification corresponds to a dental implant or a holewhich is planned to be defined in the mandibular or maxillary foraccepting said dental implant.

25. The method according to any of the preceding embodiments wherein themodification is planned based on information relating to the internalstructure and/or the surface of the second object.

26. The method according to any of the preceding embodiments wherein theplanned modification is taken into account when deriving the firstpreferred relative arrangement from said 3D model.

27. The method according to any of the preceding embodiments wherein the3D model of the second object is obtained prior to the movementprocedure.

28. The method according to any of the previous embodiments, where thesecond object comprises a part a patient body, such as a region of thepatient body in which a surgical procedure is to be performed, such as aregion comprising skin, muscular tissue, bone structure, and/or bloodvessels.

29. The method according to any of the preceding embodiments, whereinsaid second object is a dental situation of a patient, such as a dentalsituation comprising a tooth, a part of a tooth and/or at least part ofthe mandibular or maxillary bone of the patient, and where the 3D modelof the second object is obtained by scanning the dental situation, suchas by scanning the dental situation by means of an intraoral scanner orscanning an impression of the dental situation.

30. The method according to any of the previous embodiments, whereinobtaining said 3D model comprises a scanning of the surface of thescanned region of said second object.

31. The method according to any of the previous embodiments, whereinobtaining said 3D model comprises a sub-surface scanning of the scannedregion and/or target region of said second object, such as by MagneticResonance Imaging, by an X-ray scanning or by a CT scanning of thesecond object, such that the 3D model comprises an interior structure ofthe second object.

32. The method according to any of the previous embodiments, wherein the3D model comprises a 2D X-ray scan of the second object arrangedrelative to a 3D scanning of the surface of the second object.

33. The method according to any of the previous embodiments, wherein theinterior structure of the second object comprises nerves, root parts ofteeth, or the mandibular and/or maxillary bone structure.

34. The method according to any of the previous embodiments, wherein theinterior structure of the second object comprises nerves, bonestructure, arteries, and veins of a patient's body.

35. The method according to any of the previous embodiments, wherein the3D model of the second object is obtained by combining data obtained byscanning its surface and data obtained by scanning its interiorstructure, such that the 3D model comprises data relating to the surfaceand data relating to the interior structure of the second object.

36. The method according to any of the previous embodiments, wherein 3Dscanning a region of the second object provides a mapping of the surfaceof the second object in the scanned region

37. The method according to any of the previous embodiments, wherein 3Dscanning a region of the second object provides a mapping of an interiorpart of the second object in the scanned region.

38. The method according to any of the previous embodiments, whereinsaid information is displayed by projecting a guiding signal onto aregion of the second object.

39. The method according to any of the previous embodiments, wherein theregion of the second object onto which the guiding signal is projectedcomprises the target region or at least part of said target region.

40. The method according to any of the previous embodiments, whereinsaid information displaying device of the 3D guiding system comprises adisplay and said information is displayed on said display as a guidingsignal.

41. The method according to any of the previous embodiments, whereinsaid guiding signal comprises a positioning signal.

42. The method according to embodiment 41, wherein said positioningsignal shows the position of the target region on said second object.

43. The method according to embodiment 41 or 42, wherein saidpositioning signal provides information relating to the relativeposition of the first object and the second object.

44. The method according to any of the previous embodiments, whereinsaid guiding signal comprises an orientation signal.

45. The method according to embodiment 44, wherein said orientationsignal provides information relating to the relative orientation of thefirst object and the second object.

46. The method according to embodiment 44 or 45, wherein saidorientation signal provides information relating to a difference in theorientation of the present relative arrangement compared to theorientation of the first preferred relative arrangement.

47. The method according to any of the previous embodiments, whereinsaid positioning signal comprises a relatively brighter spot and saidorientation signal comprises a relatively less bright spot.

48. The method according to any of the previous embodiments, whereinsaid positioning signal comprises a relatively smaller area spot andsaid orientation signal comprises a relatively larger area spot.

49. The method according to any of the previous embodiments, whereinsaid positioning signal comprises a positioning color code configuredsuch that the color of the position indicator changes when the first andsecond objects are approaching the first preferred relative arrangement.

50. The method according to any of the previous embodiments, whereinsaid orientation signal comprises an orientation color code configuredsuch that the color of the orientation indicator changes when the firstand second objects are approaching the first preferred relativearrangement.

51. The method according to any of the previous embodiments, wherein across sectional geometry of said positioning signal and/or of saidorientation signal is selected from the group of a cross, a dot, acircle, or a polygon, such as a triangle, a square, rectangle, or apentagon.

52. The method according to any of the previous embodiments, wherein theguiding signal comprises an indicator signal, and wherein theorientation signal coincides with said indicator signal when the firstand second objects are arranged according to the orientation of thefirst preferred relative arrangement.

53. The method according to any of the previous embodiments, wherein theguiding signal comprises a distance indicator providing informationrelating to the distance between the first and second objects.

54. The method according to any of the previous embodiments, whereinsaid positioning signal and said orientation signal are arrangedconcentrically at least for some arrangements of the first and secondobjects.

55. The method according to any of the previous embodiments, wherein apre-process plan is provided, said pre-process plan describing apreferred path for the relative arrangement of the first and secondobjects during their relative movement towards the first preferredrelative arrangement.

56. The method according to any of the previous embodiments, wherein thepreferred path substantially is followed as the first and second objectsapproach the first preferred relative arrangement.

57. The method according to any of the previous embodiments, whereindeviations form said preferred path are corrected real-time by eitherbringing the relative movement back to the planned preferred path or byreal-time adapting the path.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or additional objects, features and advantages of thepresent disclosure, will be further elucidated by the followingillustrative and non-limiting detailed description of embodiments of thepresent disclosure, with reference to the appended drawings, wherein:

FIG. 1 shows a schematic presentation of a first object and a secondobject where a 3D guiding system is attached to the first object.

FIGS. 2a and 2b show a schematic presentation of a dental application ofthe disclosure.

FIGS. 3a, 3b and 3c illustrate a guiding signal according to thedisclosure and the change of the guiding signal during a relativemovement of the first and second objects.

FIGS. 4a and 4b illustrate a guiding signal according to the disclosureand the change of the guiding signal during a relative movement of thefirst and second objects.

FIG. 5 shows a schematic of a method according to the present disclosure

FIG. 6 shows a schematic of a first object with a 3D guiding systemaccording to the present disclosure.

FIGS. 7 and 8 show a schematic of how an embodiment of the 3D guidingsystem guides the first object towards a first preferred relativearrangement.

In the following description, reference is made to the accompanyingfigures, which show by way of illustration how the disclosure may bepracticed.

FIG. 1 shows a schematic presentation of a first object and a secondobject with a 3D guiding system attached to the first object.

The first object 11 has at its distal end a structure 13 which isconfigured to mate with a recess 14 at the target region of the secondobject 12. In this example the first preferred relative arrangement issuch that the structure 13 is mated with the recess 14. The 3D guidingsystem 15 is attached to the first object 11, such that it can provide3D scanning of the surface of the second object as the first and secondobjects approach the first preferred relative arrangement.

The relative movement of the first object 11 and the second object 12may be provided by an operator or by e.g. a robotic device notillustrated in the figure. During the relative motion the guiding system15 provides a real-time 3D scanning of the second object and the resultof the 3D scanning is used for calculating information that is providedto e.g. an operator in real-time in the form of a guiding signalprojected onto the second object.

In this example, the recess is visible such that the first preferredrelative arrangement easily can be identified by an operator. In manyapplications, the first preferred relative arrangement is not visuallyaccessible, but depends in an inner structure of the second object. Thecan e.g. be the case in a dental procedure, where the roots of apatient's tooth influences the first preferred relative arrangement, orin a surgical procedure where the position of bone structure andarteries below the patient's skin can be of importance.

FIG. 2 shows a schematic presentation of a dental application of thedisclosure.

In FIG. 2a , the first object is a dental drilling tool 21 while thesecond object is part of the dental situation of a patient. In thisexample, the method and the 3D guiding system is described in relationto a procedure for preparing the patient's mandibular or maxillary bonefor accepting a dental implant, but the disclosure is generic and is notlimited to this dental application. The drilling procedure is forproviding a hole in the mandibular or the maxillary bone such that theimplant may be arranged as a root-form endosseous implant.

The 3D model can be formed by combining surface data from a surfacescanning and data relating to the interior structure obtained by X-raybased scanning showing the interior structure of at least part of theset of teeth and the mandibular or maxillary bone. Preferably thescanning showing the interior structure provides information relating tothe location of the nerves in the set of teeth, such as the inferiorAlveolar nerve and/or the mental nerve, such that the guiding system canguide the motion of the drilling tool in a manner whereby drilling intothese nerves is prevented. The sub-surface scanning determining theinterior structure of the tooth may comprise a CT scanning of the dentalsituation. The tooth originally being located at the site where theimplant is to be arranged may have been removed prior to the drilling.The first preferred relative arrangement may thus be such that thedrilling tool when starting to drill will provide the hole for theimplant without colliding with the nerves.

The 3D guiding system 25 is attached to the dental drilling tool 21. The3D scanner of the 3D guiding system may be configured for intraoralscanning of the teeth to provide a virtual 3D representation of the setof teeth, from which virtual 3D representation a new 3D model of thedental situation may be determined on the fly. From a comparison of thenew 3D model and the obtained 3D model, the present relative arrangementmay be determined. A guiding signal 26 is projected on the target regionof a tooth 24 by the 3D guiding system. The guiding signal illustratedhere is a slightly deformed circular structure due to the shape of thetooth. The guiding signal 26 comprises a position signal and anorientation signal here illustrated as a dot in the center and the outerring, respectively. The inner one of the two rings is an indicatorsignal ring showing the inclination of the first preferred relativearrangement. The 3D guiding system 25 is configured for directing theguiding signal onto the target region where the dental drilling tool 21must drill into the tooth. The guiding signal 26 may be directed usinge.g. mirrors or optical waveguides, such as optical waveguides.

The guiding signal can also be visualized by an information displayingdevice on which the information is visualized using e.g. a screen. Thescreen can be an integral part of the 3D guiding system.

FIG. 2b shows a close-up of the tooth 24 and guiding signal of FIG. 2a ,where the guiding signal consist of the position signal 37, an indicatorsignal ring 40, and an orientation signal with an orientation signalring 38 and an orientation signal dot 39. The orientation signal dot 39and the indicator signal ring 40 show the azimuthal angle and theinclination of the first preferred relative arrangement, respectively.

FIG. 3 illustrates a guiding signal according to the disclosure and thechange of the guiding signal during a relative movement of the first andsecond objects.

The first object 31 may e.g. be a scalpel configured for cutting intothe second object, i.e. into the patient. The FIGS. 3a-3c illustrate thechange of the guiding signal 36 as the scalpel approaches the skin ofthe patient to a first preferred relative arrangement where the distalend of the scalpel is in contact with the target region of the patientskin.

In FIG. 3a the scalpel is not in contact with the patient skin. The 3Dguiding system 3D scans the surface of the patient, calculates theinformation, and projects the guiding signal 36 onto the patient skinthereby guiding the surgeon to the target region of the skin. Theguiding signal 36 comprises a position signal 37 and an orientationsignal 38, 39. Here the orientation signal comprises an orientationsignal ring 38 (full line circle) and an orientation signal dot 39. Theorientation signal ring 38 provides a measure of the inclination of thescalpel in the present relative arrangement. The indicator signal ring40 (dotted line circle) of the indicator signal shows the inclination ofthe first preferred relative arrangement. The orientation signal dot 39shows the azimuthal angle of the first preferred relative arrangement.

In FIG. 3b the scalpel has been placed such that its distal end contactsthe patient skin at the target region and such that the azimuthal angleof the present relative arrangement matches that of the first preferredrelative arrangement. Compared with the present relative arrangement ofFIG. 3a the inclination is also closer to the first preferred relativearrangement as seen by the decrease in the radius of the orientationsignal ring 38 towards the indicator signal ring 40.

In FIG. 3c the inclination of the scalpel is optimized such that theorientation signal ring (full line) coincides with the indicator signalring (dotted line). The scalpel is now arranged according to the firstpreferred relative arrangement and the surgeon is ready to perform a cutinto the patient's skin.

FIG. 4 illustrates a guiding signal according to the disclosure and thechange of the guiding signal during a relative movement of the first andsecond objects.

In FIG. 4, the preferred relative arrangement of the scalpel and thepatients skin/body changes as the surgeon cuts into the patient and afurther preferred relative arrangement is illustrated in FIG. 4b . Herethe azimuthal angle of the further preferred relative arrangementdiffers from that of the first preferred relative arrangement asindicated by the movement of the orientation signal dot 39 and thesurgeon needs to adjust the azimuthal angle of the scalpel relative tothe body. In real-life, the change between preferred relativearrangements may often be smooth and gradual.

The steps illustrated in FIGS. 3 and 4 are generic for the disclosureand a similar relative movement could be seen for a dental treatment ora welding of two metal plates.

FIG. 5 shows a schematic of a method according to the present disclosureInitially in step 101 the first object is obtained. On the first object,a 3D guiding system is attached, where said 3D guiding system comprisesa 3D scanner.

In step 102 the second object and a 3D model of the second object isobtained. The second object and the 3D model of this may have aninterior structure which is to be kept clear of during a modification ofthe second object.

In step 103, a first preferred relative arrangement between the firstand second objects is derived from said 3D model. The first preferredrelative arrangement may such that the first object keeps clear of theinterior structure during a modification of the second object by thefirst object.

The movement procedure comprises steps 104-106:

In step 104 a 3D scanning at least a region of said second object usingsaid 3D scanner is performed and a present relative arrangement of thefirst and second objects is determined from a result of the 3D scanning.

In step 105 the information for guiding the relative movement of thefirst and second objects towards said first preferred relativearrangement from said present relative arrangement is calculated.

In step 106 a relative movement of said first and second objects towardsthe first preferred relative arrangement is provided, where thecalculated information is used for guiding the relative movement.

FIG. 6 shows a schematic of a first object with a 3D guiding systemaccording to the present disclosure.

The 3D guiding system is attached to a dental drilling tool 21 with adistal end 211. The 3D guiding system comprises a 3D scanner 251configured for performing a 3D scanning of the second object when thisis arranged within the view of the 3D scanner 251. The 3D guiding systemfurther comprises a non-transitory computer-readable medium 252. Thismedium stores a 3D model of the second object and various program codefor e.g. determining a present relative arrangement of the first andsecond objects from a result of a 3D scanning of the second object, andfor calculating information for guiding the relative movement of thefirst and second objects towards a first preferred relative arrangementfrom said present relative arrangement. Based on the calculatedinformation, the information displaying device 253 (here a laser systemconfigured for providing the guiding signal) projects the guiding signalonto the target region of the second object (here a dental situation).The dental situation can be a tooth from which the drill is intended toremove tooth material, or a maxillary or mandibular bone into which thedrill is intended to form a hole for an implant.

FIGS. 7 and 8 shows a schematic of how an embodiment of the 3D guidingsystem guides the first object towards a first preferred relativearrangement. The 3D guiding system is attached onto the first object 21(here illustrated as a dental drilling tool) and comprises a 3D scanner251 configured for performing a 3D scanning of a region of the secondobject 12. The 3D guiding system further comprises a non-transitorycomputer-readable medium 252 and an information displaying device 253,which here is a laser system configured for projecting the guidingsignal 26 onto the target region 121 of the second object 12. Programcode stored on the non-transitory computer-readable medium 252calculates information relating to where the guiding signal 26 is to beprojected on the second object 12, and actuators and/or opticalcomponents in the information displaying device 253 are controlled basedon this information such that the guiding signal is projected onto thecorrect part of the second object. The shape of the guiding signal andthe direction in which it is emitted is adjusted as the relativeposition of the first and second objects changes. FIG. 8 illustrates thesituation where the first object is brought closer to the second objectthan in FIG. 7, and where the first object has been moved slightly alongthe surface of the second object. The direction of the guiding signal isaccordingly adjusted such that the guiding signal still is projectedonto the target region. Further the shape is adjusted if the relativeorientation changes.

Some embodiments have been described and shown in detail, the disclosureis not restricted to them, but may also be embodied in other ways withinthe scope of the subject matter defined in the following claims. Inparticular, it is to be understood that other embodiments may beutilised and structural and functional modifications may be made withoutdeparting from the scope of the present disclosure.

In device claims enumerating several means, several of these means canbe embodied by one and the same item of hardware. The mere fact thatcertain measures are recited in mutually different dependent claims ordescribed in different embodiments does not indicate that a combinationof these measures cannot be used to advantage.

A claim may refer to any of the preceding claims, and “any” isunderstood to mean “any one or more” of the preceding claims.

It should be emphasized that the term “comprises/comprising” when usedin this specification is taken to specify the presence of statedfeatures, integers, steps or components but does not preclude thepresence or addition of one or more other features, integers, steps,components or groups thereof.

The features of the method described above and in the following may beimplemented in software and carried out on a data processing system orother processing means caused by the execution of computer-executableinstructions. The instructions may be program code means loaded in amemory, such as a RAM, from a storage medium or from another computervia a computer network. Alternatively, the described features may beimplemented by hardwired circuitry instead of software or in combinationwith software.

1-18. (canceled)
 19. An intraoral 3D scanner, comprising: a probe lightsource configured to generate a probe light such that the probe light istransmitted towards the dental situation; a camera comprising an arrayof sensor elements, the camera being arranged such that the probe lightbeing returned from the dental situation is transmitted to the array ofsensor elements, wherein the camera is configured to create images ofthe dental situation from which a point cloud is generated, and aguiding system configured to guide the relative movement of theintraoral 3D scanner towards the dental situation, wherein the camera ispart of the guiding system, the camera is configured to record imagesfrom which a relative position of the intraoral 3D scanner and thedental situation is determined, such that based on the relativeposition, the guiding system is configured to provide a positioningsignal in the form of a positioning color code.
 20. The intraoral 3Dscanner according to claim 19, where a dental tool is attached to theintraoral scanner.
 21. The intraoral 3D scanner according to claim 20,where the dental tool is a drill.
 22. The intraoral 3D scanner accordingto claim 21, where in a first preferred relative arrangement at least aportion of the drill is located below a surface of a tooth or amandibular or maxillary bone of a patient.
 23. The intraoral 3D scanneraccording claim 20, wherein the intraoral 3D scanner comprises programcode for deriving preferred relative arrangements between the dentaltool and the dental situation, and wherein the preferred relativearrangements form a preferred path of the relative movement of thedental tool towards the dental situation, and said intraoral 3D scanneris configured to guide said relative movement according to saidpreferred path.
 24. The intraoral 3D scanner according to claim 23,wherein said preferred path is configured to provide that the dentaltool when guided along the preferred path will drill a hole into themandibular or maxillary jaw bone.
 25. The intraoral 3D scanner accordingto claim 19, further comprising an information display device fordisplaying the positioning signal.
 26. The intraoral 3D scanneraccording to claim 19, wherein the intraoral 3D scanner furthercomprises a first optical system for imaging with a first depth of fieldon the camera at least part of the transmitted light returned from thedental situation to the array of sensor elements and a focus planeshifting device configured for varying the position of the focus planeon the dental situation.
 27. The intraoral 3D scanner according to claim19, wherein the intraoral 3D scanner is further configured to obtain atleast one image from said array of sensor elements and to determine thein-focus position(s) of each of a plurality of the sensor elements for arange of focus plane positions, or each of a plurality of groups of thesensor elements for a range of focus plane positions.
 28. The intraoral3D scanner according to claim 27, wherein the intraoral 3D scanner isfurther configured to transform the in-focus data into 3D coordinates.